1. Technical Field
The present invention relates to a covering of a building opening, and more particularly to a window covering which is operated in an easy and less-strength way.
2. Description of Related Art
A conventional window covering includes a headrail, a bottom rail, and slats between the headrail and the bottom rail. The conventional window covering usually has two cords, each of which has an end fixed to the bottom rail, and then passing through the slats (this section is called lift cord), running over pulleys in the headrail, and then extending out of the headrail (this section is called control cord). Therefore, a user may pull or release the control cords to lift or lower the bottom rail.
In the view of consumers, except the look of the covering, the function and operation are important issues when they are going to buy a window covering. For example, whether the cord is easy to be pulled is an important concern when the consumers choose the window covering with the cords.
For the balance of the bottom rail, there needs two or more cords in the conventional window covering, which means there will be a plurality of control cords. The control cords are always easily getting twist after pulling or releasing for several times, and the twisted control cords are harmful to lift and lower the bottom rail. Furthermore, multiple control cords may lead to accidents. Children might be strangled by the loop created by the twisted control cords. In addition, sometime the control cords are not moved synchronously, and that will make the bottom rail lean. In some window coverings, they provide a cord connector to collect the control cords, however, it only has limited function.